1. Field of the Invention
The present invention relates to a guidable bogie truck, and especially a guidable bogie truck which can support a mobile crane.
2. The Prior Art
Large and heavy gantry cranes, which are, for example, used to load and unload goods from ships in harbors, are frequently constructed to move along guide rails on the ground to enable them to be moved from one work site to another by operators who have little experience. However, because the guide rails will be fixed in position, these gantry cranes are limited as to the different sites to which they can be moved, and in addition the guide rail systems are in and of themselves expensive and time consuming to construct and maintain. On the other hand, although mobile gantry cranes which can move independently of guide rails will have a much greater versatility, the opportunities for accidents and/or damage to the crane structures is very great, and only very experienced operators can be used to control their movements.
At the same time, however, at many locations (especially in underdeveloped countries) the availability of experienced operators may be very limited and the terrain around the freight loading and unloading sites may be in bad condition. Thus mobile gantry cranes which are movable independently of guide rail systems, and which would be of the needed size, although economically advantageous to use, cannot be employed.
It is an object of the present invention to provide a guidable bogie truck for mobile cranes, especially mobile gantry cranes, which can be easily operated by unskilled (although necessarily conscientious) operators, such that the mobile cranes can be successfully used even at sites which may be in bad condition.